java springboot的增删改查

其他 2019-10-26 11:50:47 阅读次数: 0

我用的是ide；参考学习地址：http://how2j.cn/k/tmall_springboot/tmall_springboot-1891/1891.html；我只是记录下笔记

要配置的引用，我用的是jdk1.8

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
    </parent>
    <dependencies>
        <!-- springboot web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- springboot tomcat 支持 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <!-- 热部署 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <!-- jpa-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <!-- redis -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
        <!-- springboot test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- thymeleaf -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <!-- elastic search -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
        </dependency>
        <!-- 用了 elasticsearch 就要加这么一个，不然要com.sun.jna.Native 错误 -->
        <dependency>
            <groupId>com.sun.jna</groupId>
            <artifactId>jna</artifactId>
            <version>3.0.9</version>
        </dependency>

        <!-- thymeleaf legacyhtml5 模式支持 -->
        <dependency>
            <groupId>net.sourceforge.nekohtml</groupId>
            <artifactId>nekohtml</artifactId>
            <version>1.9.22</version>
        </dependency>
        <!-- 测试支持 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <!-- tomcat的支持.-->
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <version>8.5.23</version>
        </dependency>
        <!-- mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.21</version>
        </dependency>

        <!-- junit -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version> 4.12</version>
        </dependency>
        <!-- commons-lang -->
        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>
        <!-- shiro -->
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-spring</artifactId>
            <version>1.3.2</version>
        </dependency>
        <!-- hsqldb -->
        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
        </dependency>
    </dependencies>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

然后配置文件application.properties

#database
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/tmall_springboot?characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto = none

#thymeleaf
spring.thymeleaf.mode=LEGACYHTML5 #html语法不用很严谨
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.content-type=text/html
spring.thymeleaf.cache=false


#context  http://localhost:8080/tmall_springboot/
server.context-path=/tmall_springboot

#设置上传文件大小，默认只有1 m
spring.http.multipart.maxFileSize=100Mb
spring.http.multipart.maxRequestSize=100Mb

#jpa对实体类的默认字段会把驼峰命名的属性，转换为字段名的时候自动加上下划线。 这个配置的作用就是去掉下划线
#比如属性名称是 createDate, jpa 默认转换为字段名 create_Date。 有了这个配置之后，就会转换为同名字段 createDate
spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

#显示 hibernate运行的 sql 语句
spring.jpa.show-sql=true

然后按照参考网站copy代码

先添加模型

package com.how2java.tmall.pojo;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@Entity
@Table(name = "category")
//jpa json会忽略这两个属性
@JsonIgnoreProperties({ "handler","hibernateLazyInitializer" })

public class Category {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)//自增id
    @Column(name = "id")
    int id;

    String name;

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

用的是springdatajap，参考博客：https://www.cnblogs.com/yeqingxue/p/11153721.html

package com.how2java.tmall.dao;

import org.springframework.data.jpa.repository.JpaRepository;

import com.how2java.tmall.pojo.Category;

public interface CategoryDAO extends JpaRepository<Category,Integer>{

}

在添加一个jpa服务，操作数据

package com.how2java.tmall.service;

import java.util.List;

import com.how2java.tmall.util.Page4Navigator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;

import com.how2java.tmall.dao.CategoryDAO;
import com.how2java.tmall.pojo.Category;

@Service
public class CategoryService {
    @Autowired
    CategoryDAO categoryDAO;

    public List<Category> list() {
        Sort sort = new Sort(Sort.Direction.DESC, "id");
        return categoryDAO.findAll(sort);
    }

    public Page4Navigator<Category> list(int start, int size, int navigatePages) {
        Sort sort = new Sort(Sort.Direction.DESC, "id");
        Pageable pageable = new PageRequest(start, size,sort);
        Page pageFromJPA =categoryDAO.findAll(pageable);

        return new Page4Navigator<>(pageFromJPA,navigatePages);
    }

    public void add(Category bean) {
        categoryDAO.save(bean);
    }

    public void delete(int id) {
        categoryDAO.delete(id);
    }

    public Category get(int id) {
        Category c= categoryDAO.findOne(id);
        return c;
    }
    public void update(Category bean) {
        categoryDAO.save(bean);
    }
}

然后添加控制器，一个是视图控制器，一个是操作数据控制器

package com.how2java.tmall.web;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class AdminPageController {
    @GetMapping(value="/admin")
    public String admin(){
        return "redirect:admin_category_list";
    }

    @GetMapping(value="/admin_category_list")
    public String listCategory(){
        return "admin/listCategory";
    }

    @GetMapping(value="/admin_category_edit")
    public String editCategory(){
        return "admin/editCategory";
    }
}
package com.how2java.tmall.web;
 
import com.how2java.tmall.pojo.Category;
import com.how2java.tmall.service.CategoryService;
import com.how2java.tmall.util.ImageUtil;
import com.how2java.tmall.util.Page4Navigator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.List;
  
@RestController
public class CategoryController {
    @Autowired
    CategoryService categoryService;

    @GetMapping("/categories")
    public Page4Navigator<Category> list(@RequestParam(value = "start", defaultValue = "0") int start, @RequestParam(value = "size", defaultValue = "5") int size) throws Exception {
        start = start<0?0:start;
        Page4Navigator<Category> page =categoryService.list(start, size, 5);  //5表示导航分页最多有5个，像 [1,2,3,4,5] 这样
        return page;
    }

    @PostMapping("/categories")
    public Object add(Category bean, MultipartFile image, HttpServletRequest request) throws Exception {
        categoryService.add(bean);
        saveOrUpdateImageFile(bean, image, request);
        return bean;
    }

    public void saveOrUpdateImageFile(Category bean, MultipartFile image, HttpServletRequest request)
            throws IOException {
        File imageFolder= new File(request.getServletContext().getRealPath("img/category"));
        File file = new File(imageFolder,bean.getId()+".jpg");
        if(!file.getParentFile().exists())
            file.getParentFile().mkdirs();
        image.transferTo(file);
        BufferedImage img = ImageUtil.change2jpg(file);
        ImageIO.write(img, "jpg", file);
    }

    @DeleteMapping("/categories/{id}")
    public String delete(@PathVariable("id") int id, HttpServletRequest request)  throws Exception {
        categoryService.delete(id);
        File  imageFolder= new File(request.getServletContext().getRealPath("img/category"));
        File file = new File(imageFolder,id+".jpg");
        file.delete();
        return null;
    }

    @GetMapping("/categories/{id}")
    public Category get(@PathVariable("id") int id) throws Exception {
        Category bean=categoryService.get(id);
        return bean;
    }

    @PutMapping("/categories/{id}")
    public Object update(Category bean, MultipartFile image, HttpServletRequest request) throws Exception {
        String name = request.getParameter("name");
        bean.setName(name);
        categoryService.update(bean);

        if(image!=null) {
            saveOrUpdateImageFile(bean, image, request);
        }
        return bean;
    }
}

然后是通用的分页和图片上传

package com.how2java.tmall.util;

import java.util.List;

import org.springframework.data.domain.Page;

public class Page4Navigator<T> {
    Page<T> pageFromJPA;
    int navigatePages;

    int totalPages;

    int number;

    long totalElements;

    int size;

    int numberOfElements;

    List<T> content;

    boolean isHasContent;

    boolean first;

    boolean last;

    boolean isHasNext;

    boolean isHasPrevious;

    int[] navigatepageNums;

    public Page4Navigator() {
        //这个空的分页是为了 Redis 从 json格式转换为 Page4Navigator 对象而专门提供的
    }

    public Page4Navigator(Page<T> pageFromJPA,int navigatePages) {
        this.pageFromJPA = pageFromJPA;
        this.navigatePages = navigatePages;

        totalPages = pageFromJPA.getTotalPages();

        number  = pageFromJPA.getNumber() ;

        totalElements = pageFromJPA.getTotalElements();

        size = pageFromJPA.getSize();

        numberOfElements = pageFromJPA.getNumberOfElements();

        content = pageFromJPA.getContent();

        isHasContent = pageFromJPA.hasContent();

        first = pageFromJPA.isFirst();

        last = pageFromJPA.isLast();

        isHasNext = pageFromJPA.hasNext();

        isHasPrevious  = pageFromJPA.hasPrevious();

        calcNavigatepageNums();

    }

    private void calcNavigatepageNums() {
        int navigatepageNums[];
        int totalPages = getTotalPages();
        int num = getNumber();
        //当总页数小于或等于导航页码数时
        if (totalPages <= navigatePages) {
            navigatepageNums = new int[totalPages];
            for (int i = 0; i < totalPages; i++) {
                navigatepageNums[i] = i + 1;
            }
        } else { //当总页数大于导航页码数时
            navigatepageNums = new int[navigatePages];
            int startNum = num - navigatePages / 2;
            int endNum = num + navigatePages / 2;

            if (startNum < 1) {
                startNum = 1;
                //(最前navigatePages页
                for (int i = 0; i < navigatePages; i++) {
                    navigatepageNums[i] = startNum++;
                }
            } else if (endNum > totalPages) {
                endNum = totalPages;
                //最后navigatePages页
                for (int i = navigatePages - 1; i >= 0; i--) {
                    navigatepageNums[i] = endNum--;
                }
            } else {
                //所有中间页
                for (int i = 0; i < navigatePages; i++) {
                    navigatepageNums[i] = startNum++;
                }
            }
        }
        this.navigatepageNums = navigatepageNums;
    }

    public int getNavigatePages() {
        return navigatePages;
    }

    public void setNavigatePages(int navigatePages) {
        this.navigatePages = navigatePages;
    }

    public int getTotalPages() {
        return totalPages;
    }

    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }

    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
    }

    public long getTotalElements() {
        return totalElements;
    }

    public void setTotalElements(long totalElements) {
        this.totalElements = totalElements;
    }

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public int getNumberOfElements() {
        return numberOfElements;
    }

    public void setNumberOfElements(int numberOfElements) {
        this.numberOfElements = numberOfElements;
    }

    public List<T> getContent() {
        return content;
    }

    public void setContent(List<T> content) {
        this.content = content;
    }

    public boolean isHasContent() {
        return isHasContent;
    }

    public void setHasContent(boolean isHasContent) {
        this.isHasContent = isHasContent;
    }

    public boolean isFirst() {
        return first;
    }

    public void setFirst(boolean first) {
        this.first = first;
    }

    public boolean isLast() {
        return last;
    }

    public void setLast(boolean last) {
        this.last = last;
    }

    public boolean isHasNext() {
        return isHasNext;
    }

    public void setHasNext(boolean isHasNext) {
        this.isHasNext = isHasNext;
    }

    public boolean isHasPrevious() {
        return isHasPrevious;
    }

    public void setHasPrevious(boolean isHasPrevious) {
        this.isHasPrevious = isHasPrevious;
    }

    public int[] getNavigatepageNums() {
        return navigatepageNums;
    }

    public void setNavigatepageNums(int[] navigatepageNums) {
        this.navigatepageNums = navigatepageNums;
    }

}
package com.how2java.tmall.util;

import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferInt;
import java.awt.image.DirectColorModel;
import java.awt.image.PixelGrabber;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class ImageUtil {

    public static BufferedImage change2jpg(File f) {
        try {
            Image i = Toolkit.getDefaultToolkit().createImage(f.getAbsolutePath());
            PixelGrabber pg = new PixelGrabber(i, 0, 0, -1, -1, true);
            pg.grabPixels();
            int width = pg.getWidth(), height = pg.getHeight();
            final int[] RGB_MASKS = { 0xFF0000, 0xFF00, 0xFF };
            final ColorModel RGB_OPAQUE = new DirectColorModel(32, RGB_MASKS[0], RGB_MASKS[1], RGB_MASKS[2]);
            DataBuffer buffer = new DataBufferInt((int[]) pg.getPixels(), pg.getWidth() * pg.getHeight());
            WritableRaster raster = Raster.createPackedRaster(buffer, width, height, width, RGB_MASKS, null);
            BufferedImage img = new BufferedImage(RGB_OPAQUE, raster, false, null);
            return img;
        } catch (InterruptedException e) {
            e.printStackTrace();
            return null;
        }
    }

    public static void resizeImage(File srcFile, int width,int height, File destFile) {
        try {
            if(!destFile.getParentFile().exists())
                destFile.getParentFile().mkdirs();
            Image i = ImageIO.read(srcFile);
            i = resizeImage(i, width, height);
            ImageIO.write((RenderedImage) i, "jpg", destFile);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static Image resizeImage(Image srcImage, int width, int height) {
        try {

            BufferedImage buffImg = null;
            buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            buffImg.getGraphics().drawImage(srcImage.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0, 0, null);

            return buffImg;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

}

然后一个全局异常处理

package com.how2java.tmall.exception;

import javax.servlet.http.HttpServletRequest;

import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestController;

@RestController
@ControllerAdvice
public class GloabalExceptionHandler {
    @ExceptionHandler(value = Exception.class)
    public String defaultErrorHandler(HttpServletRequest req, Exception e) throws Exception {
        e.printStackTrace();
        Class constraintViolationException = Class.forName("org.hibernate.exception.ConstraintViolationException");
        if(null!=e.getCause()  && constraintViolationException==e.getCause().getClass()) {
            return "违反了约束，多半是外键约束";
        }
        return e.getMessage();
    }

}

一个跨域的，但是现在没用

package com.how2java.tmall.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class CORSConfiguration extends WebMvcConfigurerAdapter{
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        //所有请求都允许跨域
        registry.addMapping("/**")
                .allowedOrigins("*")
                .allowedMethods("*")
                .allowedHeaders("*");
    }
}

主要的是application启动

package com.how2java.tmall;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);    
    }
}

然后把视图文件加上：http://how2j.cn/k/tmall_springboot/tmall_springboot-1891/1891.html

 然后增； 删；改；分页；上传图片就完成了

 

 出现thymeleaf的问题：我用replace找不到页面，然后改成了include就解决了

 

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